Conventionally, there has been known a seat used for airplanes, ships, rail road vehicles and so on which consists of a seat back 51 having a top portion equipped with a headrest 52 hingedly supported on a hinge point 53 so as to be tiltable forward with respect to the seat back 51.
However, in the above conventional case, all of the headrest 52 is constituted to be tiltable forward with respect to the seat back 51 by being tilted about the hinge point 53. Therefore, in the case where some passengers walk an aisle in an airplane by holding the headrests 52 which are tilted forward, there is a problem such that the headrests 52 moves unintentionally and causes a passenger seated on the seat trouble.
Furthermore, when a passenger room of an airplane is cleaned up or a passenger car of a train is cleaned up at a terminal station, if numerous headrests of seats are tilted forward, it requires a large manpower to return these headrests to their original positions, and also it would be a time-consuming work.
The present invention has been done in view of the above problems and disadvantages encountered in the prior art, and has an object to provide a headrest for seats in which only an upper central portion of a seat back is capable of tilting forward so as to be used as a headrest, and capable of automatically returning this headrest to its original position by tilting it forward more than a predetermined angle with respect to the seat back.